Ordered two new bulbs and replaced them. The lights have two settings and only one bulb was working on the dimmest setting. The repair was easy. The new lights are so bright and arrived quickly. I will definitely order again.

An Internet search revealed that problems like this are typically caused by one of the safety interlock switches operated by the door latches. In this particular model there is one on the top latch and two on the bottom latch. They were easy to get to by simply removing the cover. I checked the switches with an ohmmeter with the door both open and closed and found that the top switch was nearly shorted when it should have been open. The microswitches are all mounted in a plastic bracket that's mounted with just two easily accessible screws. Once the screws are removed the bracket can be pulled out into a position that makes it easy to get to the switches. I pulled off the electrical connectors (both connected to each other and come off together) and the switch comes out easily by just pushing a couple of lock tabs out of the way. Popped the new switch in, put the connectors back on, put the bracket back in place and put the cover back on. Voila! A $24.00 total cost and less than a half hour of labor.